Form error and form success Liquid for accessible Shopify themes - https://www.shopify.com/partners/blog/developing-shopify-themes-with-accessibility-in-mind

developing-accessible-shopify-themes-form-error-form-success.liquid

{% form ‘new_comment’, article %}
  {{ form.errors | default_errors }}

  <label for=”CommentAuthor” class=”hidden-label”>Name</label>
  <input {% if form.errors contains 'author' %}class=”error”{% endif %} type=”text” name=”comment[author]” placeholder=”Name” id=”CommentAuthor” value=”{{ form.author }}”>

  <label for=”CommentEmail” class=”hidden-label”>Email</label>
  <input {% if form.errors contains 'email' %}class=”error”{% endif %} type=”email” name=”comment[email]” placeholder=”email” id=”CommentEmail” value=”{{ form.email }}” autocorrect=”off” autocapitalize=”off”>
{% endform %}